While not for Epson, I can tell you that my new Epson PCK3HD inkset is actually better than the results obtained for the Pro 9500 in the link above. This inkset has gone through a lot of testing and if now ready for release. I will be posting it on my website this coming weekend. You will get very close or near OEM performance..at a very reasonable cost.
I don't know, the latest was the release of inks suitable for the Epson P600 by Lyson mid of last year with a better black level than other inks, and other companies most likely following. I don't know whether other colors of that inkset got improved and how. I have seen over time that the paper , the coating has as well a significant impact on the overall gloss appearance of different ink sets.